Paxinos and Watson spent seven years combining the latest international brain research with old fashioned anatomy studies to create an atlas of the chicken brain.

The result is the most sophisticated map of a brain ever published, charting more than 100 new areas.

In particular, the atlas shows for the first time the 11 different units of the Rhombomeres area of the brain.

This area of the brain stem is home to the Hox genes, which are responsible for foetal development and control things like breathing and heart rate.

"Knowing where each of those units are is useful in analysing things like breathing disorders, and perhaps even autism, which is suspected to be related to the Hox genes," says Watson.

Similarities between human and chicken brains

Although humans have a large cerebral cortex, brains among mammals and birds tend to be remarkably similar.

Chickens, along with rats and mice, are commonly used in research aimed at understanding human brains, particularly early brain development, because scientists have easier access to the embryo in the egg.

"The research they do with the spinal cord in chickens is amazing and it simply couldn't be done on mice," says Watson.

"Because there's been no anatomy of the chicken bits, there have been fewer studies on the connections in the chicken brain. Now, with accurate coordinates, we're hoping that more can be done."

Low tech methods

Despite developments such as MRI, much brain mapping is still done using slices of the brain, photographs, 2B pencils and tracing paper, says Watson.

And he says mapping uncharted areas involves a fair bit of interpretation.

"You use any other information you can find, and you argue until you find consensus. Then we put lines around stuff and decide. But we've rarely been wrong."